Pregnancy Flashcards
Dizygotic twinning
two eggs released and fertilized by two different sperm
Monozygotic twinning - split 0-4 days
morula
embryo splits during cleavage divisions
two separate amnions and chorions (dichorionic/diamniotic)
Monozygotic twinning - split4-8 days
splits at blastocyst stage
two separate amnions but shared chorion
(monochorionic/diamniotic)
Monozygotic twinning - split 8-12 days
splits at bilaminar embryonic disc
shared chorion and amnion (monochorionic/monoamniotic)
Monozygotic twinning - split >13 days
embryo split incomplete –> conjoined twins
Amnion vs chorion
amnion - thin inner membrane
Chorion - thick outer membrane
Trophoblast differentiation
Syncytiotrophoblasts
- closest to mom
- produce hCG
- invade endometrium, form lacunae
Cytotrophoblasts
- closest to fetus
- form chorionic villi - O2 nutrient exchange in lacunae
Ectopic pregnancy
98% in fallopian tube - ampulla
ovary, abdomen
Risk factors: prior ectopic pregnancy, hx of tubal surgery, hx of PID, smoking, infertility, IUD
Sx:
Classic triad: amenorrhea, vaginal bleeding, abd pain
referred pain to shoulder
Rupture –> severe abdominal pain
urge to defecate - pooling in pouch of douglas
dizziness
lower abdominal tenderness
adnexal mass
rebound tenderness, guarding
Dx: b-hCG (not zero but not normal levels), pelvic ultrasound
Tx: surgery, methotrexate
Partial hydatidiform mole
2 sperm + 1 egg –> 69 XXX/XXY/XYY
Fetal parts present
Chorionic villi present
normal uterine size or less than days
elevated hCG
3-5% risk of invasive mole
No risk of cancer
US: grape like clusters; snowstorm appearance of chorionic villi
Tx: D and C, follow hCG to 0
Complete hydatidiform mole
1 sperm or 2 sperm + 1 empty egg = 46 XX/XY
No fetal parts
Chorionic villi present
uterine size less than days
significantly elevated hCG
15-20% risk invasive mole
2.5% risk of choriocarcinoma
US: grape like clusters; snowstorm appearance of chorionic villi
Tx: D and C, follow hCG to 0
Invasive mole
more common in complete moles
invade locally through uterine wall –> uterine rupture and hemorrhage
Tx: chemo - methotrexate, surgery, follow hCG to 0
Choriocarcinoma
metastatic/malignant form
mets to lung!, vagina, brain, liver
50% complete moles, miscarriages, normal pregnancy, ectopic pregnancy, spontaneous
Blood brown vaginal discharge lasting months after delivery
hCG extremely high
Urachus
derived from proximal part of allantois
runs between fetal bladder and umbilicus
destined to become umbilical ligament - covered by median fold
if does not involute –> vesicourachal diverticulum, urachal cyst, patent urachus
Vitelline duct aka omphalomesenteric duct
connects the yolk sac to the lumen of the midgut - disappears by week 6 of development
remains:
vitelline fistula - meconium from umbilicus
Meckel diverticulum - lower GI bleed
Oligohydramnios
placental insufficiency, b/l renal agenesis (Potter sequence), obstruction of urine flow (posterior urethral valves - males)
2nd half of pregnancy, fetal urine most important source of amniotic fluid
polyhydramnios
esophageal or duodenal atresia, anencephaly, multiple gestations, uncontrolled maternal DM (glycosuria), congenital infections (parvovirus B19), fetal anemia d/t Rh alloimmunization
Elevated AFP
abdominal defects - gastroschisis, omphalocele
neural tufe defects
multiple gestations
incorrect dating
Triple/quadruple screen timing and components
15-20 weeks
AFP
Estriol (placenta)
hCG
Quad - inhibin
Trisomy 18 vs 21 results of triple/quad screening
18: low AFP, estriol, hCG - everything is low
21: hCG and inhibin high, AFP and estriol low
Amniocentesis
fetal cells
-genetic testings - karyotype
neural tube defects
Chorionic villus sampling
placental sample
genetic testing
10-13 weeks
Physiologic changes in pregnancy
BMR increases 10-20%
plasma volume increases 30-50%, RBC volume increases 20-30% –> physiologic anemia of pregnancy
Cardiac output increases 30-50%
-90% systolic ejection murmur, some S3
BP decreases in early pregnancy –> nadir 24-26 weeks, return to pre-pregnancy by term
Increase GFR –> decreased BUN and Cr
Increased procoagulation factors –> hypercoagulable state
-first few weeks of postpartum as well
Placenta previa
placenta overlies cervical os
Risk factors:
increased maternal age
increased multiparity
hx of c-section
Painless vaginal bleeding late in pregnancy
dx: US BEFORE digital exam
Tx: c-section
Placenta accreta vs placenta increta vs placenta percreta
Accreta: placenta adherence to myometrium
Increta: invasion into myometrium
Percreta: penetrate through uterus –> bowel and bladder
All associated w/ placenta previa and prior c-sections
Dx: US
Tx: c-section - risk life threatening hemorrhage
Hysterectomy
Placental abruption (abruptio placentae)
premature separation of placenta
hematoma between uterus and placenta
can lead to DIC
Risk factors: hx of prior placental abruption htn trauma smoking *cocaine use*
Sudden onset painful vaginal bleeding –> fast labor
contractions
fetal distress on HR monitor
Tx: emergency C section
Uterine atony
enlarged soft, boggy uterus
Risk factors: overdistended uterus - large fetus, multifetal gestation, induced or augmented labor, prolonged labor
“over worked”
Most common cause of postpartum hemorrhage
dont get myometrial contraction to close spiral a., stay open –> bleeding
Causes of postpartum hemorrhage
Uterine atony
Retained placental tissue - prevents myometrium from contracting down
genital lacerations
abnormal placentation - placenta accreta/increta/percreta
uterine rupture - rare but serious
coagulation defects
Chronic hypertension in pregnancy
HTN before pregnancy
ACEI teratogen
Meds in pregnancy:
Methyl DOPA - central a2 receptor agonist
Labetalol - alpha/beta blocker
Gestational HTN
arises during pregnancy, resolves postpartum
new onset >140/90 after 20 weeks
no proteinemia
monitor for progression
Pre-eclampsia
gestation htn + proteinuria OR end organ dysfunction
widespread endothelial vessel dysfunction –> leaky
Risk: hx of preeclampsia extremes of age nulliparity chronic HTN DM multifetal gestations hydatidiform moles
Dx: >140/90 after 20 wks
Proteinuria >= 300 mg/24 hours
If no proteinuria: thormobcytopenia, renal insuffiency, elevated LFTs, pulmonary edema, cerebral or visual sx
Severe pre-eclampsia
end organ dysfunction
BP >160/110
HELLP Syndrome
Hemolysis
Elevated Liver enzymes
Low Platelets
Eclampsia
seizure
tx; MgSO4
Treatment of severe preeclampsia, HELLP sn, eclampsia
Rapid acting anti-htn - hydralazine, labetalol, nifedipine to prevent stroke or placental abruption
MgSO4 to prevent seizure
Delivery
Human placental lactogen (HPL)
produced by placenta
decreased insulin sensitivity in mom so more glucose available to fetus
exaggerated response –> gestational DM
Gestational diabetes
develops during pregnancy, resolves postpartum
screen w/ OGTT between 24-28 weeks gestation
Manage: diet +/- insulin
Complications:
macrosomia
hypoglycemia after delivery: high glucose state in utero –> beta cells hyperplasia in pancreas –> increased insulin –> hypoglycemia
Pregestational diabetes
Overt DM prior to pregnancy
Insulin mgmt
Complications:
macrosomia
hypoglycemia
congenital anomalies: cardiac defects, caudal regression syndrome (sacral dysgenesis - lower body doesn’t form properly), still birth, deliver earlier
Terbutaline
asthma and tocolytic
selective B2 agonist –> uterine relaxation
SE: tachycardia, hypotension, pulmonary edema
Ritodrine
preterm labor
not used in US
Prostaglandin drugs
Cause cervical dilation and uterine contraction
early –> termination
Late –> induce
Dinoprostone - PGE2
Misoprostol PGE1
Misoprostol
PGE1
also used in PUD, keep PDA open
SE: excessive uterine stimulation –> fetal distress, uterine rupture
Mifepristone (RU486)
competitive antagonist at progesterone receptor
antiprogesterone
Early –> blastocyst detach, myometrium contract –> termination
Give w/ misoprostol
SE: vaginal bleeding, abdominal pain/cramping, N/V/D
